Nano- and micro-sized particles to which bio-materials are bound have been applied to biosensing, bioimaging, isolation, and the like, in various fields such as food, health care, diagnosis, and life science. For example, an antibody-magnetic nanoparticle conjugate and an antibody-gold nanoparticle have been used for detecting a target material by a bond between an antigen and an antibody in an immune sensor (Yu-Hui Bai. et al., Anal. 135:1672-1679, 2010).
One of factors having a significant effect on formation of an antigen-antibody reaction conjugate is an antibody immobilization method, and therefore, various immobilization technologies have been developed, and there are various methods for binding protein. For example, there are a method using chemical and physical adsorption, a method for binding protein to a gold nanoparticle using cystein which is an amino acid specifically bound to gold, a method for producing a monomolecular film on a gold nanoparticle and then covalently binding protein to the gold nanoparticle using a functional group of the monomolecular film, and a method for adsorbing avidin protein on a surface of the gold nanoparticle and binding protein to which biotin is bound (ZHANG zhiFeng et al., Sci china ser B-Chem. 50(1):127-134, 2007), and the like.
However, currently developed immobilization technology according to the related art has problems in that conditions of immobilization reaction such as pH are varied depending on properties of protein, and in a case of a nanoparticle, dispersion is not achieved but nanoparticles are flocculated.
Korean Patent No. 0962286 discloses a magnetic core gold nanoparticle for detecting food-borne pathogens, a manufacturing method thereof, and a detecting method of food-borne pathogens using the nanoparticle, which is characterized by including: preparing a magnetic body core containing magnetic materials; modifying a surface of the magnetic body core with an amine functional group; and forming a gold particle layer on a surface of the magnetic body core surface-modified with the amine functional group.
However, the above-mentioned patent has problems in that reproducibility or efficiency of a chemical reaction generated at the time of modifying the surface of the magnetic body core with the amine functional group may be deteriorated and flocculation phenomenon in a solution may occur. In addition, significantly long reaction time is required for forming a gold particle layer, and food-borne pathogens enable to be detected only by a separate equipment, SPR, which is inconvenient.
Accordingly, the present inventors found that in a case of coating a first nanoparticle having magnetic or fluorescent characteristics with protein, manufacturing a conjugate by adsorbing a second nanoparticle having metallic characteristics onto the first nanoparticle, and adsorbing a bio-material onto the conjugate, precipitation of the nanoparticles may be prevented and the bio-material may be easily immobilized without performing an inconvenient modification process, and desired materials are capable of multi-functionally detected and isolated using properties of the protein coating the first nanoparticle and properties of the bio-material adsorbed onto the second nanoparticle, thereby completing the present invention.